This invention relates to an improved ABS resinous plastic composition.
ABS resins are extremely popular for many uses because of their desirable physical properties and especially the high-impact strength, tensile strength, chemical resistance and heat resistance. One of the chief uses of ABS resins is for pipes, such as drain, waste and vent pipes.
One of the chief reasons that ABS plastics have not been used more widely is due to their relatively high cost, as compared to other plastics such as polyvinylchloride. In order to overcome the cost factor, there has been a major effort to incorporate various low cost filler materials in ABS compositions. Materials such as talc, calcium carbonate, and clay have been used to extend the material and reduce the overall cost per ton. One of the drawbacks of these materials has been that in many instances the reduction in cost has been achieved by substantial sacrifice in impact strength and other important properties.
Recently, asphalt has been utilized as an additive to ABS compositions to thereby lower the cost of the composition while not greatly reducing the impact strength and other key physical properties. Such an improved composition is taught in U.S. Pat. No. 3,926,884, incorporated herein by reference. However, even with the asphalt additive, it has been found from a commercial point of view that as the proportion of asphalt is increased above a very low level, such as 2% by weight, the impact strength and tensile strength begin to drop off rapidly. Thus, the amount of cost reduction that can be achieved through the use of asphalt as an additive to the ABS plastics is very limited.